How to Write a Metal AM RFQ

Writing an RFQ for metal additive manufacturing (AM) is less about “getting a price” and more about locking down manufacturability, compliance, and acceptance criteria before the first build starts. A strong RFQ reduces change orders, prevents schedule slips, and ensures you receive parts that meet engineering intent—especially when the workflow includes powder bed fusion (PBF) such as DMLS / SLM, Hot Isostatic Pressing (HIP), precision CNC machining, and regulated documentation for defense and aerospace programs.

This guide focuses on what to include in an rfq for metal 3d printing so suppliers can quote accurately and you can compare bids apples-to-apples. The sections below reflect how successful programs structure RFQs when they need repeatable quality, material traceability, and audit-ready certification packs under AS9100, NADCAP, ITAR, and DFARS expectations.

What files to include

Start by assuming your supplier will build a traveler, inspection plan, and CNC setup directly from what you provide. If the RFQ package is incomplete, the shop either bakes assumptions into the quote (risk) or returns with questions (delay). A robust RFQ package typically includes the following.

1) Native CAD + neutral CAD
Provide the native CAD file (e.g., SolidWorks, NX, Creo) and a neutral file (STEP AP242 is common). Native files help suppliers interpret design intent, while STEP helps downstream programming and quoting when native formats are incompatible.

2) 2D drawing with revision control
Even if the part is “model-based,” include a controlled drawing or MBD dataset defining: dimensions/GD&T, datums, tolerances, surface finish, material/spec, heat treat, notes, and inspection requirements. Ensure the RFQ clearly states the current revision and that all files match.

3) Build intent notes (when you have them)
If your engineering team has preferences, state them as “preferred” vs “required” so the supplier can propose alternatives. Examples include: preferred build orientation, areas where support contact is unacceptable, and any “keep-out” regions for witness coupons or support scars.

4) Post-processing and machining model (recommended)
If the part requires CNC finish machining, provide either: (a) an as-built AM model plus machining model, or (b) one model with explicit machining stock allowances called out. For many PBF components, a practical RFQ approach is to specify minimum machining stock on critical surfaces (e.g., +0.5 mm) and allow the supplier to recommend stock elsewhere based on distortion risk.

5) Assembly context and interfaces
For procurement-ready quoting, include interface information that affects CTQs: mating parts, gasket/seal locations, fastener type, torque requirements, and whether the part is pressure-containing or structural. If you can’t share full assemblies (ITAR/program constraints), at least provide interface geometry and functional requirements.

6) Quality and compliance requirements document
If your organization has a supplier quality clause set (AS9100 flow-downs, ITAR handling, DFARS specialty metals, record retention), attach it. Otherwise, state the minimum requirements in the RFQ itself so quotes include the cost/time for compliance.

Practical tip: Include a one-page RFQ “cover sheet” that summarizes part number, revision, quantity, material, required certifications, delivery date, and point of contact. This reduces misquotes caused by buried requirements.

Tolerances and critical-to-quality

Metal AM is powerful, but it is not “print-to-final” for most defense/aerospace hardware. RFQs fail when they treat AM like a commodity machining job or, conversely, when they assign overly tight tolerances everywhere. The best RFQs separate what must be precise from what can be left as-built.

1) Identify CTQs explicitly
Create a short CTQ list in the RFQ or on the drawing. CTQs are the features that drive function, safety, or qualification, such as:

• sealing surfaces and grooves
• bearing seats, bores, and coaxial features
• threaded holes and insert interfaces
• load-path features and minimum wall thickness in stressed regions
• internal passages (minimum diameter, true position, leak performance)

When CTQs are called out, suppliers can plan the workflow correctly: AM for near-net geometry, HIP for densification if needed, then 3- or 5-axis CNC machining to final size on CTQ features using stable datums.

2) Use datums that match the real manufacturing sequence
If datums reference as-built AM surfaces that will be removed during machining, inspection becomes ambiguous. A more reliable approach is to define machined datum targets or datum features that will exist after a designated machining operation. This helps the supplier design fixtures and reduces inspection disputes.

3) Be realistic about as-built AM tolerances
For PBF, as-built geometry can vary due to thermal distortion, support strategy, and feature size. RFQs should avoid blanket tight tolerances on all surfaces. Instead:

• Specify tight tolerances only on features that will be machined.
• For as-built regions, specify allowable envelope or profile tolerances appropriate to the process and application.
• Call out minimum wall thickness and “no un-melted powder trapped” requirements for internal cavities (with a defined verification method).

4) Surface finish: specify where it matters
As-built PBF surfaces are typically rougher than machined surfaces and can vary by orientation. If surface finish affects fatigue, sealing, flow, or coating adhesion, call it out on the drawing and clarify whether the finish is required as-built or after machining / abrasive finishing. Also specify whether media blasting is allowed (and what media), since contamination control can matter for oxygen-sensitive alloys.

5) Define what “acceptable distortion” means
If flatness, straightness, or positional accuracy matters after stress relief/HIP and machining, state it. A good RFQ also asks the supplier to include their planned sequence (e.g., stress relief → rough machine → HIP → finish machine) because sequence impacts final geometry.

Material and heat treat

Material definition for AM is broader than alloy name. For aerospace and defense procurement, you want to lock down the specification pedigree, the powder control plan, and the post-build thermal history that drives properties.

1) Specify alloy and governing specification
Instead of “Inconel” or “Ti64,” specify a recognized material standard or customer spec. Examples commonly used in AM programs include Ti-6Al-4V (and Ti-6Al-4V ELI), Inconel 718, 17-4 PH, and aluminum alloys such as AlSi10Mg—each with application-dependent requirements. In your RFQ, define:

• alloy designation and required chemistry limits (by spec)
• minimum mechanical properties and test temperature if applicable
• any restrictions on recycled powder, powder blending, or number of re-use cycles

2) Powder traceability and handling requirements
Ask for traceability that links each part to: powder lot, machine/build ID, build parameters (at least at the controlled plan level), and post-processing batches. For regulated programs, clarify whether you require:

• material certifications for powder (chemistry, particle size distribution, flow, oxygen/nitrogen where relevant)
• controlled storage and handling (humidity/oxygen controls for reactive powders)
• documented sieving and contamination controls

3) Define the thermal processing route
Metal AM parts often require thermal processing to reduce residual stress and to stabilize microstructure. Your RFQ should state whether the supplier is responsible for:

• stress relief (often required for PBF before separation from the build plate or before machining)
• HIP (densification to reduce internal porosity and improve fatigue performance; common for critical aerospace structures)
• heat treatment such as solution/age (e.g., for precipitation-hardening alloys) or anneal

Also specify whether HIP must be performed to a particular industry-accepted cycle (time/temperature/pressure) and whether HIP must be performed by a NADCAP-accredited processor (common in aerospace supply chains). If HIP is required, clarify coupon strategy and whether tensile specimens must be HIP’d with the parts in the same load and cycle.

4) PM-HIP vs PBF: avoid ambiguity
Some programs use PM-HIP (powder metallurgy + HIP in a can) instead of PBF. If you are open to either approach, state it explicitly and ask the supplier to propose. If you require PBF (DMLS / SLM) for geometric reasons (lattice, internal channels), say so. Procurement confusion here can result in quotes that are not comparable.

5) Post-processing beyond heat treat
If you expect additional post-processing—support removal, bead blasting, abrasive flow machining for internal passages, shot peen for fatigue, coating, or passivation—state what is allowed and what is prohibited. For example, specify whether any chemical cleaning steps must be compatible with downstream bonding, welding, or coating.

Inspection requirements

Inspection is where RFQs either become predictable—or turn into disputes. A procurement-ready RFQ defines what must be verified, how it must be verified, and what records must be delivered.

1) Start with the acceptance package
Define the minimum “cert pack” content you expect with shipment. Typical aerospace/defense expectations include:

• Certificate of Conformance (CoC) referencing part number, revision, quantity, and applicable specs
• material traceability package (powder lot certs, heat numbers where applicable, build ID traceability)
• heat treat / HIP charts or certifications tied to batch/serial numbers
• dimensional inspection report with measured CTQs
• nonconformance documentation and approved deviations, if any

If you require AS9102 First Article Inspection (FAI), state whether it is required for the first lot, after design revision, after process change, or after relocation of manufacturing.

2) Define dimensional inspection method
For machined CTQ features, CMM inspection is common. If you require CMM, specify whether you need: full CMM report, point-to-point checks, or a ballooned drawing. For as-built AM features, clarify whether optical scanning (structured light) is acceptable and how it maps to acceptance criteria (e.g., profile-of-surface tolerance).

3) NDE for internal integrity
AM can create internal features and also internal discontinuities; the right NDE depends on risk. In your RFQ, state whether you require any of the following and for what regions:

• CT scanning (industrial computed tomography) for internal channels, lattice, or porosity evaluation
• dye penetrant inspection (PT) for surface-breaking indications after machining
• radiography (RT) where applicable for volumetric defects
• ultrasonic testing (UT) for thicker sections (geometry-dependent)

CT scanning is particularly useful when internal passage cleanliness, minimum diameter, or trapped powder risk is high. If you require CT, specify the deliverables: pass/fail only, defect map, voxel size/resolution, and data retention expectations.

4) Mechanical testing and witness coupons
For qualified or flight-critical hardware, mechanical properties often must be validated with witness coupons built alongside the part or within the same build configuration. Your RFQ should clarify:

• coupon type (tensile, fatigue, density), orientation (X/Y/Z), and quantity
• whether coupons must follow the same thermal processing (stress relief, HIP, heat treat) as the parts
• whether results must meet minimum allowables or simply be reported

5) Calibration, records, and audit readiness
State that inspection equipment must be calibrated and traceable, and clarify record retention period if your program requires it. If your procurement flow-down requires AS9100 or equivalent QMS, note it. If you require NADCAP for heat treat or NDT, state it upfront so suppliers do not underquote.

6) ITAR and controlled technical data handling
If the part/data is ITAR-controlled, the RFQ should state ITAR applicability and require the supplier to confirm controlled-access procedures (data storage, access controls, visitor control, and personnel authorization). This is not just legal language—it directly affects who can run the job, where it can be processed, and how quickly it can move.

Lead time and delivery

Lead time in metal AM is driven by more than machine hours. The RFQ should prompt suppliers to quote a complete manufacturing schedule including post-processing, HIP, machining, inspection, and documentation.

1) Separate “print time” from end-to-end lead time
A realistic schedule includes: job planning, build slot availability, printing, cool-down, depowdering, stress relief, part removal, support removal, HIP (if required), rough/finish machining, inspection/NDE, and final documentation. Ask suppliers to provide lead time in these phases, especially for first articles.

2) Clarify quantity, lotting, and scalability
State prototype quantity versus production quantity and whether you expect repeat orders. If production is anticipated, ask the supplier to quote: (a) first lot lead time and price, (b) recurring lot lead time and price, and (c) capacity assumptions (build volume utilization, number of machines, HIP batch size constraints).

3) Define delivery terms and packaging
AM parts can be sensitive to handling damage and contamination. Specify packaging expectations: clean, protected surfaces; corrosion protection where needed; individual bagging; and labeling that maintains traceability (serial/lot, part number, revision). If you need partial shipments, state whether they are allowed.

4) Address schedule risk up front
Include RFQ questions that expose schedule risk, such as:

• Which post-process steps are in-house vs subcontracted (HIP, NADCAP heat treat, CT scanning)?
• What are the supplier’s current lead times for those subcontractors?
• What is the plan if a build fails (rebuild lead time, powder quarantine procedure)?

5) Expedite options
If you have a hard program need, ask for an expedite path: premium machine slotting, parallel machining/inspection planning, or pre-approved process plans. Also clarify what can and cannot be compressed (for example, some thermal cycles and inspection steps are fixed).

Common RFQ mistakes

Most RFQ problems are preventable. These are recurring issues that create inaccurate quotes, quality escapes, or late deliveries in metal AM programs.

1) Missing or conflicting revisions
Quoting from Rev A drawing and Rev B CAD is a classic failure mode. Always include a revision table or a single source of truth, and require the supplier to list the file names/revisions they quoted.

2) Unclear scope: “printed part” vs finished, inspectable hardware
If you need a production-ready component, the RFQ must say so. “Print only” might exclude HIP, CNC machining, NDE, cleaning, serialization, FAI, and cert packs. Be explicit about the deliverable state: as-built, HIP’d, machined, inspected, and documented.

3) Over-tolerancing everything
Applying tight tolerances to nonfunctional surfaces forces unnecessary machining, complex fixturing, and scrap risk. Identify CTQs and allow the rest to be controlled by reasonable as-built acceptance criteria.

4) Not defining internal feature requirements
Internal channels are a common reason to choose AM, but they must be specified properly: minimum diameter, allowable roughness, powder removal strategy, and verification method (e.g., CT scanning). Without this, quotes will vary widely and parts may fail functional tests.

5) Omitting thermal processing requirements (or assuming them)
Whether you need stress relief, HIP, solution/age, or other heat treat must be stated. The thermal route changes mechanical properties, distortion behavior, and cost. If you are uncertain, ask suppliers to propose a baseline route and include alternates as line items.

6) Failing to flow down compliance early (ITAR/DFARS/AS9100/NADCAP)
If you add ITAR or NADCAP requirements after award, you risk re-quoting and re-sourcing. Put flow-downs in the RFQ so only qualified suppliers respond and prices reflect compliance.

7) Not asking for the manufacturing plan assumptions
Two suppliers can quote the same geometry but assume different orientations, support strategies, machining datums, or inspection methods—leading to non-comparable bids. Request a brief “quote basis” statement including: assumed orientation, key post-process steps, which surfaces will be machined, and planned inspection approach for CTQs.

RFQ checklist you can reuse (include in the RFQ email or portal)
Part number/revision; quantity and delivery date; CAD + drawing; CTQ list; material/spec; powder control expectations; stress relief/HIP/heat treat requirements; machining scope and stock allowances; surface finish requirements; NDE (CT/RT/UT/PT) requirements; dimensional inspection (CMM/scan) requirements; FAI requirement; CoC and traceability package; ITAR/DFARS/AS9100/NADCAP flow-downs; packaging/labeling/serialization; quote basis assumptions requested.

When your RFQ includes these elements, suppliers can respond with accurate, comparable quotes—and you gain the documentation and process control needed to move from prototype to production with confidence.